Conventionally, a transfer apparatus, which transfers an image (mirror image) formed on a transfer film to a card using a heat roller (FIR), has been known widely. Generally, this type of transfer apparatus adopts a configuration in which the heat roller is pressed against a surface on the side opposite to a transfer surface of a transfer film and the transfer film and a card are concurrently transported (at the same velocity).
In such a transfer apparatus, by heat being applied to the card from the heat roller, materials (for example, PVC) of the card expand, and a curl occurs in the card by a force spread outward and an inclusion force due to the heat roller in peeling off the image from the transfer surface of the transfer film. Therefore, the transfer apparatus is provided with a decurl mechanism that corrects the curl of the card, and after transferring the image to the card, decurl processing to correct the curl of the card is performed using the decurl mechanism.
For example, Patent Document 1 discloses techniques for transporting the card to the decurl mechanism to halt at the center arrival time in performing decurl processing, pressing a decurl unit (pressing member) downward, and performing the decurl processing on the card for a time set by a user. In the techniques, as shown in FIG. 23A, by pressing the other surface (upper surface in the figure) side of the card with an image transferred to one surface (lower surface in the figure) side having a curl using the pressing member constituting the decurl mechanism for a predetermined time (A seconds) to correct (remove) the curl of the card, the card is rotated 180° (reverse the frontside and backside), and as shown in FIG. 23B, the pressing member presses one surface (upper surface in the figure) side of the card with the image transferred to the other surface (lower surface in the figure) side having the curl similarly for the predetermined time (A seconds) to correct the curl. In other words, in the techniques of Patent Document 1, both in the case of transferring an image to only one surface (FIG. 23A) and in the case of transferring images to both surfaces (see FIG. 23B), the curl of the card is corrected by pressing the card with the decurl unit for the same time (A seconds) to provide the card excellent in handling and appearance.
In addition, as techniques related to the present invention, Patent Document 2 discloses a two-sided recording apparatus to prevent a transfer failure such as a jam from occurring on a sheet. This apparatus is provided with a guide section which passes the sheet while curving and thereby changes a curl state of the sheet, and the curl state of the sheet is corrected by varying a time for which the sheet is passed through the guide section. The time for passing through the guide section is determined corresponding to a sheet size, sheet thickness, ambient temperature of the apparatus, humidity, optional setting, fusing temperature of a heat fusing section, and sheet temperature.